UPDATE @ 3:25 p.m.: Coastal Flood Watches have been posted for rather unusual, but significant tidal flooding along the Delaware River from Trenton and points south (let alone the rain flooding that may occur) for Northwestern Burlington, Camden, Gloucester, and Salem Counties...
The east-southeast wind is already cranking across our region today. Winds are sustained 10 to 15 MPH with frequent gusts of 20 to 30 MPH. These winds will only increase as the storm system evolves and moves closer to New Jersey. Vigorous negatively tilted trough and the position of the double-barrel low pressure areas will provide a nice setup for a strong fetch off the Atlantic Ocean and it will also provide a nice setup for strong wind gusts. There is no doubt this will be a windswept rainfall. A low center may exist across the Great Lakes with another forming along the Middle Atlantic. The one across the Middle Atlantic now appears it will move from east into the interior of Central Pennsylvania. This track will really bring in that stream of moisture. Meanwhile, high pressure will be to the north and east of Maine, and that will really work to tighten the gradient. I think the strongest wind gusts will be along our coastlines of Monmouth, Ocean, Southeastern Burlington, and Cape May Counties. Wind gusts past 55 MPH wouldn’t surprise me in these eastern counties during the height of the storm. They will drop off inland, but gusts will still be in excess of 40 MPH. There is the potential for structural damage to the trees and utility poles as the ground is so saturated that these wind gusts would be capable of knocking them down. . I think we will see so much rain that many of the weakened trees even without the wind could fall with the loosened soil. Of course flood waters can also be powerful enough to take down trees. The bottom line is strong easterly to southeasterly winds can be anticipated. Behind the departing system, northwesterly to westerly winds will occur on Friday. With a high pressure area building in, some more windy conditions can be expected, albeit not as intense. The previous Sunday storm, which did not have as strong of an east-southeast setup was able to get wind gusts to 56 MPH in New York City with widespread frequent gusts of around or above 40 MPH in New Jersey. So I do have reason to believe this will be a more impacting strong to high wind event.
Coastal flooding is going to be another concern with a persistent easterly flow. I think the water will pile up fairly well along our coastal communities. Widespread minor tidal flooding looks like a good bet. Some communities should experience moderate coastal flooding with my wind projections.
It appears as though the models want to now show to distinct rounds of heavy rainfall. The one round will be the moisture that streams up from Louisiana and the Florida Panhandle where tornado watches are currently in effect. Then the second round will be the evening and nighttime round which should put many low-lying areas and eventually waterways over their banks. In-between these rounds, there could even be a brief few hour lull (lighter rain?) in the action. Two to three inches of rain will likely fall from Thursday Afternoon into Friday Morning. Some areas will see localized amounts of four to six inches. Historic flooding is quite possible in Northern New Jersey where there is still ongoing flooding around the Passaic River Basin. The water levels will drop some, but perhaps not below flood stage prior to this event. Just imagine the rises in this area this time around as last time around we at least started below flood stage. Elsewhere, even if there is not ongoing flooding, should three inches fall, significant flooding is expected if the rainfall predictions are realized. Some of the flooding could be of moderate to major severity.
Tidal effects will aggravate the flooding along the Delaware River and along the coastline. I remain persistent that anyone living in an area that has flooded in the past few decades should prepare for flooding this go around. Move furniture to higher ground and have an evacuation plan in place. During the heavy rain, flooding in most areas will occur in low spots, around ditches, streets with areas of poor drainage, and at smaller creeks and streams. Then all that water on Friday will head towards the major creeks and major rivers. The rises here will be perhaps slow as it will take time for the runoff to make its way there, although if four inches of rain falls, a much faster rise can be expected, perhaps a flashier flood. The ground is so saturated that this rain cannot be absorbed. Trees are also not sucking in the water since there are no canopies to support. Numerous road closures are expected Thursday Night and Friday Morning.
Some isolated strong to severe thunderstorms cannot be ruled out. There appears to be some marginal instability. Some embedded thunderstorms will be associated with the low as it rides up the cold front. The convection will be mainly low-topped. Strong easterly winds may be enhanced by the convection just like last March when there was a few rumbles of thunder with the monster Nor’easter. With such a well-organized rain shield, detecting microbursts and weak tornadoes are difficult and it may not necessarily happen. It will all be about the parameters in place as the convection approaches from the south. The severe weather threat will be very limited, but not impossible. Any squall-lines that form to our south will have to be watched to see if they move into our region. Lightning could be limited with any convection that does form.
The flood watch now includes all of New Jersey’s 21 Counties. I couldn’t agree with this decision more. My wind forecast is presently more robust than the National Weather Service’s wind forecast. I am well aware. The stronger winds I am expecting is like a domino effect because it is related to tidal flooding in many aspects leading to a more dramatic coastal flood forecast from me. Eventually, in time, I suspect wind advisories and coastal flood statements will be issued for the eastern counties, even if it is issued during the storm. In the March 2010 storm, there were plenty of last minute issuances and upgrades. I have enough confidence in the overall setup to take a step away from cautiousness. If there are already 29 MPH gusts in interior Burlington County, how can I go wrong with the wind forecast during the peak of the storm?
Anyway, I will be updating the forecast again late tonight and all day tomorrow I will have extensive coverage.
